I will try to help you with this question.
Now ,since the tv shuts off when you insert the tape,there are several possible causes,but all are actually on the VCR part of the set.
The first thing to check ,would the the mode select switch,under the vcr deck.
This multi position switch needs to be cleaned.
Then,another possible cause would be the tape end sensors,also on the vcr deck(this are optical sensors.
Also another cause can be the capstan (there is a magnetic sensor,that can shut the tv off ,if the capstan is not spinning ,or spins with a different speed).
I do not know,what is your technical level in the VCR field,but cleaning and aligning the VCR requires a qualified VCR tech!
Is not so simple,since there are mechanical and electronic parts,that need to be taken apart and then mounted back.
Also the VCR deck will need to be aligned once its parts are cleaned-cam gear,mode switch,etc.
If you are not comfortable to do this by yourself,I estimate this kind of labor fee around-$80-$120.
I do not think that your unit needs any parts(unless a tape was forced inside and some plastic pieces are broken)
Now since you have this information about what is going one with your unit,you can make a decision about repairing this unit or not.
Thank you for considering my answer,and have a great day!